"TarBabyTunes" wrote in message
...
I was wondering if the phenomenon was that headphones always cause
flatting.
Does anyone know if headphones may also cause sharping?

And what's that about anyway? Too much level in the headphones might cause
the tympanic membrane to be pushed slightly out of shape? Would that make
the singer's voice appear higher in pitch than it really is?

I find it to be psychological rather than physical...

I would think it was the vocal cords that are being pushed out of shape. The
singer can't hear themselves over the loud background music so they sing
harder thus "pushing sharp" via the forced air.